Here is what I believe is a complete list of the new enemies and their observed levels which may still vary. These enemies were added in the 6/6/09 update.
NATURE- Stone Crab 2-5
- Devourer Crab 19-24
- Rabid Bat 4-7
- Bayou Alligator 4-7
- Dire Scorpion 5-10
- Killer Wasp 9-14
- Soldier Wasp 18-25
- Giant Fly Trap 9-14 (renamed from Fly Trap)
- Rancid Fly Trap 13-19
- Corrupt Stump 28-35 (renamed from Stump)
NAVY- Marine 6-10 (Cutlass)
- Dragoon 24-30 (Cutlass)
UNDEAD- Undead Mutineer 4-7 (Dagger)
- Undead Brute 6-10 (Cutlass)
- Undead Duelist 13-19 (Cutlass)
- Undead Slasher 18-25 (Dagger)
- Undead Executioner 23-30 (Cutlass)